In the past, for example, a lens module having an autofocus (AF) function is used for photographing in a wide range from near distance to infinity. However, when the AF function is adopted, the number of lenses and the number of components increase and cost increases according to the increase in the number of lenses and the number of components. In particular, in a camera module used in a digital camera or the like, a distance between a lens and an imaging element (focal length) tends to be reduced as much as possible according to demands for a reduction in thickness and a reduction in size.
In recent years, a technology called EDoF (Extended Depth of Field) for securing sufficient depth of field by combining a fixed-focus lens and signal processing has been developed. Whereas a lens for AF only has to be capable of securing resolution in a focus position, the fixed-focus lens for EDoF has insufficient resolution because the depth of field is secured. For example, when a relation between depth of field and a modulation transfer function (MTF) is represented by a graph, whereas, in the lens for AF, the graph is a graph with narrow range width, in the fixed-focus lens for EDoF, the graph is a graph with wide range width. Concerning such a lens characteristic of the fixed-focus lens for EDoF, the insufficiency of the resolution is supplemented by the signal processing. Therefore, an S/N (a signal to noise ratio) tends to deteriorate in a process of the signal processing. Further, because there is a limit in supplementation of the depth of field, in general, lens design is performed with importance attached to resolution in the infinity. Therefore, it is difficult to obtain sufficient resolution in the near distance.